I was wondering if anyone could recommend a book that would help in learning informal Japanese. I hope to visit Japan this year but a few of my Japanese friends, who I write to, mention that my Japanese is very formal. They say I write to them as if they are my boss! I understand why this is - I'm learning the language largely on my own with a few internet lessons here and there. I'm using the みんなの日本語 textbook and there only seems to be one chapter in there about the plain style and informality - I'm only up to ch.32 in Book 2. I really want to soften my language for when I meet my friends in person. Has anyone any ideas?